A rendering engine library for Go supporting both SDL2 and WebAssembly (HTML Canvas) targets.
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// Package sdl provides an SDL2 renderer for Doodle.
package sdl
import (
"fmt"
"time"
"git.kirsle.net/go/render"
"git.kirsle.net/go/render/event"
"github.com/veandco/go-sdl2/sdl"
"github.com/veandco/go-sdl2/ttf"
)
// Renderer manages the SDL state.
type Renderer struct {
// Configurable fields.
title string
width int32
height int32
startTime time.Time
// Private fields.
events *event.State
window *sdl.Window
renderer *sdl.Renderer
running bool
ticks uint64
textures map[string]*Texture // cached textures
// Optimizations to minimize SDL calls.
lastColor render.Color
}
// New creates the SDL renderer.
func New(title string, width, height int) *Renderer {
return &Renderer{
events: event.NewState(),
title: title,
width: int32(width),
height: int32(height),
textures: map[string]*Texture{},
}
}
// Teardown tasks when exiting the program.
func (r *Renderer) Teardown() {
r.renderer.Destroy()
r.window.Destroy()
sdl.Quit()
}
// Setup the renderer.
func (r *Renderer) Setup() error {
// Initialize SDL.
if err := sdl.Init(sdl.INIT_EVERYTHING); err != nil {
return fmt.Errorf("sdl.Init: %s", err)
}
// Initialize SDL_TTF.
if err := ttf.Init(); err != nil {
return fmt.Errorf("ttf.Init: %s", err)
}
// Create our window.
window, err := sdl.CreateWindow(
r.title,
sdl.WINDOWPOS_CENTERED,
sdl.WINDOWPOS_CENTERED,
r.width,
r.height,
sdl.WINDOW_SHOWN|sdl.WINDOW_RESIZABLE,
)
if err != nil {
return err
}
r.window = window
// Blank out the window in white.
renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED)
if err != nil {
panic(err)
}
renderer.SetDrawBlendMode(sdl.BLENDMODE_BLEND)
r.renderer = renderer
return nil
}
// SetTitle sets the SDL window title.
func (r *Renderer) SetTitle(title string) {
r.title = title
r.window.SetTitle(title)
}
// GetTicks gets SDL's current tick count.
func (r *Renderer) GetTicks() uint32 {
return sdl.GetTicks()
}
// WindowSize returns the SDL window size.
func (r *Renderer) WindowSize() (int, int) {
w, h := r.window.GetSize()
return int(w), int(h)
}
// Present the current frame.
func (r *Renderer) Present() error {
r.renderer.Present()
return nil
}
// Delay using sdl.Delay
func (r *Renderer) Delay(time uint32) {
sdl.Delay(time)
}
// Loop is the main loop.
func (r *Renderer) Loop() error {
return nil
}